The present invention relates to regenerated collagen fibers improved in suitability for setting. More specifically, the present invention relates to regenerated collagen fibers which have light color and excellent touch in wet conditions, which can be formed into a desirable shape easily with the shape being maintained properly and whose foul odor generated in thermal treatment is inhibited. The present invention also relates to a process for preparing the same. Such regenerated collagen fibers can be suitably used for curling hair ornaments such as wigs, hairpieces and doll hair or for shaping (setting) textile goods comprising woven fabrics or non-woven fabrics.
In order to produce regenerated collagen fibers, a process is adopted in general which comprises treating skin or bone of animals as a raw material with alkali or enzyme, decomposing and removing telopeptide in collagen to make it water-soluble, and spinning the same. Herein, the obtained regenerated collagen fibers are also soluble in water. In addition, when the regenerated collagen fibers contain water, shrinking starts at about 30xc2x0 to 40xc2x0 C., meaning that water resistance thereof is extremely inferior.
To make regenerated collagen fibers water-resistant with maintaining its light color, there are processes for treating collagen fibers with metallic salt such as aluminum salt or zirconium salt as disclosed in Japanese Unexamined Patent Publication No. 50370/1992, Japanese Unexamined Patent Publication No. 173161/1994 and Japanese Unexamined Patent Publication No. 308221/1992, and a process for treating collagen fibers with an epoxy compound as disclosed in Japanese Unexamined Patent Publication No. 352804/1992. As a process for shaping regenerated collagen fibers, a process disclosed in Japanese Unexamined Patent Publication No. 333660/1992 or Japanese Unexamined Patent Publication No. 250081/1997 which comprises moisturizing fibers in warm water or an aqueous solution containing monovalent or divalent cationic hydrosulfate, and heat-treating the fibers is known. However, when the regenerated collagen fibers which are made water-resistant by the treatment with metallic salt such as aluminum salt or zirconium salt are shaped according to the above method, shape keeping ability (set property) thereof is extremely low though certain shape can be given to the fibers. Furthermore, the given shape is lost immediately when water washing (including shampoo washing) and drying are repeated. Thus, it was difficult to use these fibers for hair products such as wigs, hairpieces and doll hair.
Though light color fibers are also obtained by using formaldehyde, the obtained fibers were not satisfactory in shaping property either. Additionally, in case of using a multivalent alcohol, i.e., glycidyl ether which is regarded as the most preferable compound among epoxy compounds described in Japanese Unexamined Patent Publication No. 352804/1992, fibers became brittle and hard, and strength thereof was remarkably lost, causing problems during production process of hair ornament, for example, hair implant or sewing machine operation. Furthermore, the fibers were not satisfactory in shaping property either.
An object of the present invention is to provide regenerated collagen fibers which have light color and excellent touch in wet conditions, which can be formed into a desirable shape easily and whose setting can be carried out with maintaining the shape properly.
In view of the current conditions mentioned above, the present invention has been completed based on the findings that it is possible to obtain regenerated collagen fibers which have natural light color of collagen, improved hardness when the fibers are wet, and excellent touch in wet conditions by combining two kinds of treatment, namely, treatment by a monofunctional epoxy compound and treatment by an aluminum salt.
The present invention relates to regenerated collagen fibers which are obtained by treating collagen with a monofunctional epoxy compound and an aluminum salt.
The present invention also relates to a process for preparing regenerated collagen fibers which comprises treating collagen with a monofunctional epoxy compound and then treating the same in such a way that 2 to 40% by weight of an aluminum salt converted to an aluminum oxide (Al2O3) basis is contained to said collagen.
The present invention also relates to a process for setting regenerated collagen fibers which comprises thermally setting the regenerated collagen fibers by means of hot water treatment at 20xc2x0 to 100xc2x0 C. and heat drying treatment at 60xc2x0 to 220xc2x0 C.